1. Field of the Invention
The present invention relates to ultraviolet curing coating compositions, comprising liquid mixtures of polyethylenically unsaturated compounds and monoethylenically unsaturated hydroxy functional polyethers, which are modified to yield increased ability to withstand fabrication stresses without loss of adhesion to the substrate on elongation on ultraviolet cure followed by baking.
2. Description of the Prior Art
Ultraviolet curing liquid coating compositions based on polyethylenically unsaturated compounds are known. It would be desirable to extend the usefulness of these polyethylenically unsaturated compounds, and also to render the systems more fluid, by incorporating therein liquid monoethylenically unsaturated materials. One proposal for doing this is to employ liquid monoethylenically unsaturated hydroxy functional polyethers which can be produced by reacting a monoethylenic carboxylic acid or hydroxy ester thereof with one or more moles of an alkylene oxide, particularly propylene oxide. While the presence of the monoethylenically unsaturated hydroxy functional polyether provides liquid mixtures which cure rapidly to form a solid and nontacky film on ultraviolet light exposure, such coatings have little capacity to sustain elongation, even after baking. This causes fracturing of the coating and delamination when the coated substrate is fabricated.